Formulation of pH-responsive nanoparticles using zein/sodium alginate polymers for enhanced bioavailability of the vitamin D3.

The effective delivery of vitamin D3 (Vit D3) is challenging due to its susceptibility to degradation and low bioavailability, necessitating advanced encapsulation strategies. This research paper, therefore, focuses on the development and holistic evaluation of a pH-responsive nanoparticle system (Vit D3-Z/SA) using zein/sodium alginate (Z/SA) as carrier molecules. The nanoparticles (NPs) were optimized using the anti-solvent technique, yielding a size of <200 nm, zeta potential of -56 mV, and encapsulation efficiency of 77 %. The structural integrity was confirmed through SEM (morphology), FTIR (molecular interactions), UV-visible spectroscopy (compound stability) and TGA (thermal stability). Stability assessments demonstrated resilience under varying ionic strengths and storage conditions. The pH-responsive behavior indicated stability of the NPs above pH 3, consequently in-vitro bioaccessibility studies showed minimal releaseand sustained release of vitamin D in gastric pH (2) and intestinal pH (7.2), respectively. Further, in-vivo bioavailability in Wistar rats revealed significantly higher absorption and prolonged retention in NPs-treated groups (64.16 ng/mL) compared to free Vit D3 (18.87 ng/mL). Similarly, alkaline phosphatase assays confirmed enhanced bone mineralization in NPs treated rats (1.3-fold increase). Overall, the study highlights Z/SA nanoparticles as an effective delivery system for improving the stability and bioavailability of Vit D3, offering a promising approach for food and nutraceutical applications.